A kinetic description is presented of ponderomotive effects which originate from a time-dependent high-frequency (hf) field. The solution of the corresponding generalized diffusion equation shows the appearance of a nonlocal term which reflects a memory of the plasma. It leads to significant changes of the plasma properties during and after the duration of the hf field. The plasma is irreversibly heated and a region of high density and high temperature appears at the center of hf activity in the time asymptotic limit.

• Received 12 March 1979

DOI:https://doi.org/10.1103/PhysRevLett.42.1339